Insulated electrical conductor



J. A. KENNEDY May 1, 1934.

NSULATED ELECTRCAL CONDUCTOR Filed March 5l, 1952,

|NvENToR JJEPH /L/E/v/VED H BY H Z-VEYS M Patented May 1, 1934 PATENT OFFICE 1,956,721 INsULA'rED ELECTRICAL ooNDUC'ron Joseph A. Kennedy, Pawtucket, R. I., assignor to Anaconda Wire & Cable Company, New York, N. Y., a corporation of Delaware Application March 31, 1932, Serial N0. 602,240

7 Claims.

This invention relates to improvements in insulated conductors and more specically to that' type of conductor in which there is a layer of insulation surrounded by a jacket enclosed or impregnated with a body of stearin pitch.

It is well known in the art that such stearin pitch is desirable for use in this environment because it is substantially or approximately nonble.` But, such material is relatively sticky or tacky and has a tendency, even when given various treatments known inthe art, to become softened under the inluence of heat. Various ways have been suggested for treating such stearin pitch conductors. It has formerly been proposed to cover the pitch surface with wax. It has also been proposed to coat the same with a layer of silicate ofsoda or a layer of lacquer. 'I'he use of various gums have also been suggested. In conductors heretofore provided, several difficul- 20 ties have been experienced in imparting to the conductors a distinctive coloring.

The present invention is intended to overcome the above and other disadvantages in prior practice.

'I'he invention will be fully apparent from the vfollowing specification when read in connection with the accompanying drawing and will be pointed out with particularity in the appended claims.

In the drawing- Fig. l is an enlarged view partly in elevation and partly in sectionillustrating one embodiment of the invention;

Fig. 2 is a section on line 2 2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 illustrating a modication.

Referring detail to the drawing, may be considered either a Wire, cable or stranded conductor which is surrounded by a. body of insulation 12, such as rubber, or the like in any manner well known in the art. Over this, there is a braided, woven, or a wrapped jacket 14, which may be treated with a water-proong compound, such as asphalt or the like. In the embodiment V illustrated in the drawing, I have shown a woven sheath. Regardless of what form of jacket is used, I envelop the same with a layer 16 of stearin pitch. This material may enter between the interstices of the strands which make up the sheath and may also form a thin outer layer thereon.

The conductor thus far described may be produced in any of the prior known methods. One novel and important feature of the present invention resides in enveloping the stearinpitch r coated jacket with a body of rubber, so as to over-v come the objectional stickiness inherent in stearin pitch. In the manufacture of the conductor, I pass the stearin pitch coated conductor through a bath comprising an aqueous dispersion of rubber latex. This deposits a relatively thin film over the exterior of the layer of stearin pitch, which when exposed to air is self-curing, thus forming the outer waterproof rubber layer, indicated at 18. In order to impart any desired distinctive coloring to the outer rubber layer 18, the latex may have suitable pigments incorporated therein. These distinctive colorings will serve to identify various circuit Wires, or the polarity of the conductor.

The use of latex enables me in one operation to produce a conductor with a lm of unmasticated `rubber enveloping the stearin pitch, thus overcoming its stickiness and at the same time enables me to obtain a neat finish having a distinctive identifying color.

In some cases, instead of applying the colored latex directly to the stearin pitch, the latter may be rst covered with a thin layer of hardening material such as silicate of soda, as indicated at 20 in Fig. 3. Over this, there will be applied the 80 layer 18 of rubber, as shown.

While I have described quite precisely the particular embodiments of the invention illustrated it is to be understood that the drawing and description are to be interpreted in an illustrative rather than a limiting sense.

What I claim is:-

1. A conductor having an enclosing layer of insulation, a jacket of interconnected strands surrounding said insulation,-a body of stearin pitch 90 bonded to and enveloping said jacket and a layer of rubber in direct contact with and surrounding said body of stearin pitch.

2. A conductor having an enclosing layer of insulation, a jacket of interconnected strands surrounding said insulation-a body of stearin pitch bonded to and enveloping said jacket and a layer of unmasticated rubber which is the residuel of an original latex aqueous 'solution directly engaging 100 and surrounding said body of stearin pitch.

3. A conductor having an enclosing layer of insulation, a jacket surrounding' said insulation, a body of stearin pitch impregnating said jacket, and a layer of rubber directly engaging and surrounding said body of stearin pitch.

4. A conductor having an enclosing layer of insulation, a. jacket surrounding said insulation, a body of stearin pitch surrounding said jacket and a layer of rubber directly engaging and surrounding said body of stearin pitch said rubber having a. distinctive coloring pigment incorporated therein.

5. A conductor having an enclosing layer of insulation including a body of stearin pitch and a layer of rubber directly engaging and surrounding said body of stearin pitch.

6. A conductor having an enclosing layer of insulation including a body of stearin pitch and a iii? 

